/Engine/Source/Runtime/GeometryCore/Public/HalfspaceTypes.h
3D Halfspace stored as parameters to Plane Equation (Normal, Normal.Dot(PointOnPlane)) The Normal points "into" the halfspace, ie X is inside if (Normal.Dot(X) - Constant) >= 0
template<typename T> struct THalfspace3
T
Constant
Distance along Normal that defines position of Halfspace
TVector< T >
Normal
Normal vector of 3D plane that defines Halfspace